X-ray tube.



PATE'NTBD NCW.` 10, 1903.

J. o. HEINZRJE.

X-RAY TUBE. APPLwA'rIoN FILED JULY a, 1903'.

`No MODEL.

Tu: Norms vm'cns co, mnraumm wnsulnarm a. c

UNITED i STATES Patented November 1903.

PATENT OEETCEs JOHN o. nEiNzE, JE., or LOWELL, MASSACHUSETTS.

X-RAY TUBE.

SPECIFICATION forming part of Letters Patent No. 743,718, dated November.10, 1903.

Application tiled July 9, 1903, Serial No. 164,775. (No model.)

To @ZZ wwnt t may concern:

Be it known that I, JOHN OTTO HEINZE, Jr., a citizen of the UnitedStates of America, residing at Lowell, in the county of Middlesex andState of Massachusetts, have invented certain new and usefulImprovements in X- Ray Tubes, of which the following is a speciication.

My invention relates to X-ray tubes; and the gen eral object of myinvention is to provide an X-ray tube strong in construction andefficient in operation. I

The glass bulb of an X-ray tube musthave a large instead of a smalldiameter iino'i'der that Ysaid bulb may have there-in al stable Workingvacuum; but the thiclrixess'io'fl the Walls of such bulb to withstandthfatinospheric pressure is so great thatmsirof the energy of the raysis lost in their passage through said Walls by absorption. Further,

as the energy of X-raysfat any distance-from the lanode varies inverselyas the square,j of that distance the smaller tliediameter of the bulbthe greater the ease with. Whiclhthe rays pass through the Walls of-said bulb, and hence the greater the resulting intensitybf-the raysradiated. Still further, as the radiating-surface of said bulb is thatof a hemisphere in front of the face of the anode the rays, unlesscontrolled, radiate in many directions. In short, the bulb of an X-raytube should be strong in construction, of large diameter, be thin, andhave a small radiating-surface.

NOW the particular object of my invention is to provide an X-ray tubethat fulfils these requirements, and I accomplish this object by the useof what constitutes the novel feature of my invention-namely, arentering portion of the radiating-Wall of the bulb.

In the. drawings illustratingthe principle of my invention and the bestmode now known to me of embodying that principle, Figure 1 yis alongitudinal vertical section, and Fig. 2

is an elevation at right angles to said section.

The X-ray tube A has an anode c, a cathode a', and other elements Wellknown and usually found in an X-ray tube. B is a reentering portion ofthe radiating hemispherical Wall b of the bulb of said tube, lying infront of the face a2 of the anode a and eut ed by the plane YYcontaining said face. Said rentering portion B is formed by heating thedesired portion of said Walls constituting said radiating-surface b,said portion then being drawn or sucked in by the glass-blower. Then sodrawn, it becomes dome-shaped, its thickness diminishing from that ofthe bulb to one of extreme thinness in the portion b' near said anodeand across the X-ray paths.

In practice l have made the diameter of the bulb from eleven to twelveinches, the thickness of themain Walls one-eighth of an inch, and thethickness of the exposed dome portion h lessthan one one-hundredth of aninch. For convenience the axis s s of the dome B is at right angles tothat of the anodestem; but it may be at any other angle, provided saiddome lies in the anodes field of bombardment Y b b Y. While the shape ofsaid domeB is easily blown and results in the stron gestnon-collapsibleconstruction,yet l do not Wish to limit said rentering portion B to thatshape, for any shape whereby a small portion of the` mainradiating-Walls, thick or thin, can be brought closer than the mainWalls of the bulb to the anode Willembody niy invention.

The opcration'of my invention is as follows: lWhen a current ofelectricitypasses from the anode a to the cathode vd', X-rays aregenerated at the anode a in the Well-known manner and radiate in alldirections, impinging the hemispherical Walls ot the bulb bpb h in frontof the face a2 of the anode a. The Walls l) b b being thick and at aconsiderable distance from the anode ct, most of the X-rays areabsorbed, said hemispherical-Wallportions forming practically a shieldagainst the out- Ward passage of said rays; but these rays, striking thetop 'portion b' of the dome B and having at that distance from theanode, say, four times the energy they would have at twice thatdistance-sayat the main Walls of the bulb-readily pass through the top oof the dome Band have increased intensity--that is, their originalintensity is but slightly reduced. This would be true if the dome Wereeven of the saine thickness as the main Walls of the bulb. New if inaddition to the nearness of the top b'voi' the dome B to the anode a,said top portion is reduced in thickness, so that it is very thin,plainly very little en- ICO ergy is absorbed in the passage of said raysthrough said dome and the resulting intensity of the X-rays is stillfurther increased. In fine, by means of my invention I have an X- raytube in which there is a stable Working vacuum and with which there isradiated from a limited area X-rays having greatly increased intensity.

Having, described my invention and desiring to claim the same in thebroadest manner legally possible, what I claim isl. In an X-ray tube, ananode; a cathode; and a bulb, having' a rentering,` portion of its yWall, projecting` into theiield of bombardment bardment; said renteringportion having,`

that portion near the anode thinner in thick- Vmana ness than thethickness of the radiating-Walls of said bulb.

3. In an X-.ray tube, an anode; a cathode; and abulb, havingademe-shaped rentering portion of its radiating-Walls, projecting intothe ield of bombardment of the anode.

4. In an X-ray tube, an anode; a cathode; and a bulb, havingadome-shaped rentering portion of its radiating-walls, projecting intothe field of bombardment of the anode, and having the thickness of theportion of said dome near the anode, thinner than that of theradiating-Walls.

In testimony whereof I affix my signature in presence of two Witnesses.

JOI-IN O. HEINZE, JR.

Witnesses:

ALICE MURRAY, ANNA. E. WISE.

